Magnetic blowout



July 22, 1941. c. M. GARNER MAGNETIC BLOWOUT FiledAug. 15, 1938 P/IZ Patented July 22, 1941 MAGNETIC BLOWOUT Claude M. Garner, University City, Mo., assignor to Automatic Control Corporation, St. Loui Mo., a corporation of Delaware Y Application August 15, 193s, serial No. 224,831;

(o1. zoo-147) 7 Claims.

The -present invention relates to a magnetic arc blow-out and especially to one combined with a magnetic snap action for a switch.

It is an object of the invention to provide a suitable magnetic field desirably approximately perpendicular to the path of the potential are between switch contacts.

It is a further object of the invention to provide the said blow-out magnetic ileld in connection with a magnetic snap action for a switch.

In the drawing:

Fig. 1 is a sectional view lengthwise of a switch showing the invention;

' Fig. 2 is an end view partly in section taken on the line 2-2 of Fig. 1;

Fig. 3 is a transverse section on the line 3--3 of Fig. 1;

Fig. 4 is a top view of the magnetic block; and,

Fig. 5 is a view of one of the magnetism conducting elements.

There is here shown a switch generally indicated at IIl having a front plate II to which is attached a housing I2 and aback plate I3. A lterminal I4 is attached to the front plate II, and back of the plate II a contact bracket I5 is connected to the terminal I4. This contact bracket is bifurcated to provide opposed depending contact legs I6 and I1 having contact points Il and I3 horizontally located thereon.

Another terminal is secured to the front plate, and inside the iront plate is attached a generally rectangular contact bracket 2| having contact elements 22 and 23 thereon opposite the respective contacts I8 and I9.

To the contact plate I3 is secured the magnet block 25 which may be made of a moldable plastic material, or any other suitable substance. Embedded within this block is located a piece be observed that the two ends 28 are of opposite polarity, as also are the two legs 29.

A movable switch arm 32 carries a conductor 33 whereby it receives one end of an electric circuit. It has a somewhat resilient extension 34 of conducting material, the outer end of which is depressed downwardly and then further outwardly as shown at 35, so as. to rest adjacent the opposite legs 29 of the magnetic conductors. 'I'his end 35 likewise carries two armatures 36 and 31 spaced from each other and maintained on opposite sides of a plane including the two legs 28, by a spacer element 38. As the switch blade moves up and down, one of the two armatures 36 or 31 is brought toward the two projecting poles 28 so as to span these two poles. At the same time the other of the two armatures is carried away from the two poles. By this means 28 of magnetized metal shown in Fig. 3 to have a horseshoe shape. Above this magnet 26 and also embedded in the lblock are two angular magnetic conductors 21, symmetrically shaped, one of these being shown in Fig. 5. The middle parts oi these magnetic conductors are located alongside the magnet 26, and one adjacent -each of its poles, as shown in Fig. 3. The larger extending ends 28 of these conductors project outwardly from an edge of the block; and the shorter upstanding legs 29 project upwardly from the top of the block. When theblock is in position, the legs 23 project toward the switch contacts, one extending adjacent the contacts -I8 and 22, and the other adjacentthe contacts'l and 23.

The ends 28 project outwardlyas elements ofthe snap-action mechanism to be described. 'It will the switch is operated into either of its two positions with a snap action. s The switch blade carries also a contact plate 48 that is supported thereon for limited movement and is urged in an upward direction by a leaf spring 4I. The plate 40 is of such size as to span the' contacts 22 and 23 when in its lower position or the contacts I8 and I9 when in its upper position.

In operation, when force is applied to the switch to move it. for example, from the position shown in Fig. 1 to a position wherein the plate 40 closes with the upper contacts, the force first deforms the resilient switch arm until enough pressure is built up to overcome the force of the magnet on the armature 38. The armature breaks from the magnet, and since the intensity oi. the magnetic attraction decreases exponentially as the distance from the magnet increases, the break takes place with a snap-action. After a certain distance of travel, the armature 31 comes within the magnetic eld and is acted on by a rapidly increasing force, so that the switch moves to a top position with a snap, permitted by the resiliency of the blade.

In initiating breaking of the contacts there is a tendency for a spark to jump between the contacts being broken to the plate 40. However, there is" a magnetic field set up between the opposite poles oi the magnet, which is augmented by the two upstanding pole members 23, and this retards yformation of` any such sparks, and blows `them out. lThe path oi thismagnetic field exalsofthrough the plate 48 and to some extent through the contact elements.-

It is thus seen that there is here provided not only a desirable magnetic blow-out for a switch but also a combined magnetic blow-out and snap action. Furthermore, the use of magnetic conductors not only increases the eiciency of the blow-out, but also permits some variation in the shape of the magnet that will be dirlicult to obtain in the usual magnet.

What is claimed is:

1. A switch including a first contact, a movable blade having a second contact adapted to make and break with said first contact, an armature on said blade spaced from the contact, and an elongated magnetic element extending at one end adjacent said armature to provide a snap action for said switch blade, said magnetic element also extending at its other end adjacent the path of said switch blade away from said first contact element to establish a magnetic field to repress the formation of arcs as said blade breaks with said contact.

2. A switch including a fixed contact and a movable contact, a blade upon which the movable contact is mounted, said blade having an armature portion thereon spaced from the contact, magnet means including rst elements provid-ing a rst eld with a pair of opposite magnetic poles adjacent the opposite ends of said armature whereby said armature may conduct the magnetic eld from one pole to the other, said magnet means also having other elements extending adjacent one of said contacts to provide another magnetic eld with opposite poles, saideld being adapted to provide flux in the path made by the movable contact when it breaks with the xed contact.

3. In a switch, a pair of oppositely disposed xed contacts, a movable contact adapted to move to close selectively with one or the other of said xed contacts, a blade upon which said movable Contact is mounted, armature means on the blade, and magnetic means extending adjacent both said fixed contacts to set up a eld to repress the formation of arcs when the movable contact breaks with either and also extending adjacent said armature means so as to set up a eld to produce a snap action of the blade, said magnetic means adjacent the armature means providing opposite poles across which said armature extends when effecting the snap action.

4. In a switch mechanism, a iixed contact, a movable blade, a contact on said blade to move to or away from the xed contact, an armature on the blade and spaced from the contactfa magnetic unit including a source of magnetism, a magnetic conducting element having one end turned at an angle to the other end, said element at its mid-portion being secured adjacent the source of magnetism, and the magnetic unit being so disposed that the upturned end extends adjacent the contacts, and the otherend extends to said armature.

5. A magnetic unit including a magnet having opposite poles, an elongated magnetic conductor .adjacent each pole, each magnetic conductor presenting opposite ends polarized from the permanent magnet, the corresponding ends of the two conductors being spaced but related to establish two magnetic iields extending from one conductor to the other, and means binding the conductors and magnet together in said relationship, together with a first contact, a movable switch arm having an armature adapted to enter one magnetic field and a second contact adapted to engage the first contact, said first contact being within the other magnetic field.

6. A unit as in claim 5, wherein the magnet is a permanent one, and the two conductors and the permanent magnet are bound together by a plastic molded about them.

7. In a switch, a rst pair of spaced contacts, a second pair of spaced contacts displaced from the iirst pair, a displaceable switch blade means adapted to span either the first pair or the second pair of contacts, a pair of spaced armatures on said blade, and magnetic means having a rst set of opposite pole pieces providing a magnetic field with opposite poles adapted to be spanned respectively by either of said armatures upon displacement of -tlie blade means, said magnetic means having additional opposite pole pieces providing a magnetic field across the path of movement of the blade means as it breaks with either pair of contacts, whereby said magnetic means provides an arc blow-out and a snap-action.

CLAUDE M. GARNER. 

